Checking Fuel Injection Timing - Yanmar 4TNV98 Service Manual

2. Using the FIR number for the engine being
serviced use the Fuel Injection Reference (FIR)
Chart under "FIE Specs" on the Yanmar
Distributor Website
(http://distributor.yanmar.co.jp).
The FIR number is determined by the complete
engine model number. The engine model
number is located on the engine nameplate
(Figure 7-35).
Figure7-35
EXAMPLE: The following example is for an engine
model 4TNV98 - SDF.
• Find the engine model number in the FIR chart.
Locate and record the FIR number (The FIR
number for this engine is 4).
• Insert the numbers you have recorded into the
following equation:
(Fuel Injection Pump Timing Index Number X 2) +
FIR Number = FIT° (Fuel injection Timing in
Degrees)
(6.8 X 2) = 13.6 + 4 = 17.6° Fuel injection Timing
• Record the calculated fuel injection timing
specification.
4TNV98 & 4TNE98 Diesel Engine

Checking Fuel Injection Timing

NOTE: Some fuel may drain from the fuel injection
pump during this process. Make provisions to
contain any such spillage.
1. Turn off the fuel valve in the fuel supply hose and
the fuel return hose.
2. Clamp shut the fuel injection pump fuel return
hose leading to fuel filter (Figure 7-36, (1)).
IMPORTANTClean the top of the fuel injection
pump to prevent any contamination when the
fuel injection pump plunger plug is removed.
3. Remove the forward fuel injection pump plunger
plug (Figure 7-36, (2)) on the top of the fuel
injection pump.
4. Install a dial indicator adapter and clamp into the
pump plunger opening.
NOTE: Use the Yanmar part no. 158090-51841 for
the M16 adapter used on the MP4 fuel injection
pumps (TNV94-106 model engines) and Yanmar
part no. 23000-013000 plunger adapter clamp
(Figure 7-37, (1)).
158
Figure 7-36
IMPORTANT
Section 4. Fuel System